Lipopolysaccharide activates the muscularis macrophage network and suppresses circular smooth muscle activity

Mark K. Eskandari*, Jörg C. Kalff, Timothy R. Billiar, Kenneth K.W. Lee, Anthony J. Bauer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Bacte-rial lipopolysaccharide (LPS) is a causative agent of sepsisinduced ileus. Although it is known that LPS activates macrophages and initiates inflammation, the consequences of LPS on the macrophage network and a potential inflammatory response within the intestinal muscularis have not been investigated. This study was designed to identify cellular and functional changes in rat intestinal muscularis after intraperitoneal LPS. Histo- and immunohistochemistry were used to phenotype leukocytes. Functional alterations were determined using an organ bath. Compared with controls, LPS caused a 21-fold increase in staining for the lymphocyte activation marker-1 (LFA-1) localized to the ED2+ macrophage network l h after injection. This was followed by a significant infiltration of neutrophils, mast cells, and monocytes into the muscularis. LPS also caused a 62% reduction in spontaneous circular muscle activity and a 91% suppression of bethanechol-stimulated contractions 12 h after injection. These results demonstrate that endotoxemia 1 ) acutely activates the muscularis macrophage network, 2) causes the extravasation of leukocytes, and 3) results in circular muscle impairment.

Original languageEnglish
Pages (from-to)G679-G685
JournalAmerican Journal of Physiology
Issue number3 PART 1
StatePublished - 1997
Externally publishedYes


  • Endotoxemia
  • Inflammation
  • Lymphocyte activation marker-1
  • Motility


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